1. Field of the Invention
The present invention relates to sensor devices used in electronic devices and vehicles, including digital cameras and automobile navigation systems.
2. Background Art
As shown in FIG. 3, a conventional sensor device includes angular velocity sensor 1 for outputting an angular velocity sensing signal, and acceleration sensor 2 for outputting an acceleration sensing signal.
A prior art related to the present invention is disclosed, for example, in Japanese Patent Unexamined Publication No. 2005-283481.
However, the conventional sensor device has a disadvantage of its low detection accuracy.
Let's take an example of an automobile navigation system in a vehicle equipped with the above conventional sensor device. More specifically, let's assume that the vehicle is traveling in a multistory parking lot. The sensor device uses gravitational acceleration information from acceleration sensor 2 for correcting angular velocity information from angular velocity sensor 1. This enables detection of a spiral travel of the vehicle in the multistory parking lot.
However, in the conventional sensor device, an output on gravitational acceleration from acceleration sensor 2 and an output on angular velocity sensor 1 are not linked timewise. Accordingly, if there is a difference in signal transmission time between a circuit of angular velocity sensor 1 and a circuit of acceleration sensor 2, the angular velocity information cannot be accurately corrected using the gravitational acceleration information from acceleration sensor 2. This results in low detection accuracy.